Where does music ability originate?

In this photo is nine-year-old James. He has been playing the viola for two years and is quite accomplished. A great-grandfather of James played the violin, as did one of his great uncles. A great-grandmother played the piano very well and a second cousin is extremely musical. But neither of James’s parents is musically inclined which makes one wonder if musicality is a special and isolated genetic ‘gift’ or if it travels through the ‘blood line’, missing the occasional generation.
James’s maternal grandmother was so un-musical that, when she was a small school girl, the singing teacher would sometimes suggest a song be repeated but ‘don’t you sing this time, Fay’ was the request. Sad but true.
 
Is musical ability similar to athletic ability, where a young person that way inclined, with great practise, attains a high level of athletics or some sport?
Or is music something different; something more special?
It is obvious that there are musical people and non-musical people.
It’s a fascinating ‘condition’ that I think is far more complex than any ability for physical achievement.
Is it more akin to mathematical ability?
Musicianship must be connected more to brain activity than to physical mastery and yet there is also a sort of emotional connection to be seen in people with (advanced) musical skill.
Do mathematicians ‘lose themselves’ in a trance-like state as they work on a fascinating equation? Perhaps they do.
Or is the ability to master music simply a factor in one’s make-up, such as the characteristic of having curly or straight hair? But then hair type and body build are physical features that can be seen – and seen to have an origin.
Musical attributes are invisible.
But, fortunately for us all, they can lead to music that can be heard.